I've just found a file on Fabrice Frances website called 'Midway' which when loaded into Oricutron appears to be a 100% accurate version of "Space Invaders" (minus sound). Does anyone know if there is any way to play this? I assume it is emulated due to it's slow speed but it looks fantastic when Oricutron is set on warp mode

Even if it isn't playable I find it fascinating and it just goes to show that the Oric is capable of a near perfect conversion of the game.

Space Invaders was one of the first games I tried to write on Oric, (lost my tapes grr..) and I recall using a mix of BASIC and Assembly to do things .. scrolling/char-redefine was done with assembly, setup and scoring and so on in BASIC. Wish I had those tapes ..

A last thing to know : If none of the Joystick switches is actuated, then the six inputs will be at logic state 1. It means that when a switch is actuated, the logic status of the corresponding input changes to 0. To know the status of the JS you just have to read the port A of VIA. (LDA$301)

My JS routine simulates the use of the following Keyboard keys: left, right, up and down arrows for movements and Space bar for shoots.
All these keys are situated on the row 4 of the Matrix Keyboard. That means that the oricium keyboard routine write a value corresponding to the key pressed in $3BCC ( $3BC8,X with X=4). The values to write for each keys are: